The synthesis and characterization of the cationic manganese-porphyrin [meso-tetrakis(1-methyl-4-pyridinio)porphyrinato] manganese(III) penta-acetate complexes encapsulated in zeolite and mesoporous molecular sieve has been accomplished, and their catalytic activity was tested in the epoxidation of styrene and cyclohexene by iodosylbenzene. With mesoporous molecular sieve (MCM-41) and the new NaY zeolite (DMY) as supports, the encapsulated manganese-porphyrin systems show high activity and selectivity for the epoxidation. The effects of solvent and reaction time and the performance of the recovered catalysts have been studied. The mechanism of olefin oxidation has also been discussed. (C) 2002 Elsevier Science B.V. All rights reserved.